Underwater Hunger Artist: Giant Isopod Fasts For 4 Years

A giant isopod in Japan has refused to eat for more than four years. This specimen was caught during a NOAA expedition in the Gulf of Mexico by Bob Carney of LSU.

NOAA Ocean Explorer

Originally published on February 26, 2013 9:09 am

From Japan comes news of a giant isopod that knows all there is to know about the hunger game. How else to explain the fasting behavior of the animal that, his minders say, hasn't eaten in more than 1,500 days? The male giant isopod, known simply as No. 1, last ate on Jan. 2, 2009 — or, to put it in perspective, 18 days before President Obama began his first term.

The giant isopod's last meal at the Toba Aquarium, reports Japan Times, was a horse mackerel, which it devoured in just five minutes.

But that was four years ago. Since then, No. 1 has only pretended to eat — going so far as to rub its face on dead fish before walking away, according to reports. The aquarium's Takaya Moritaki says he has tried everything he can think of to get the finicky giant isopod, which was caught in the Gulf of Mexico, to eat.

"I just want it to eat something somehow. It's weakened in this state," he tells the Japan Daily Press. He recently invited the media to witness the giant isopod's hunger strike, as it spurned several pieces of fish. The mysterious behavior has not taken an obvious toll on No. 1, which has reportedly remained healthy during its long period of abstaining.

Giant isopods are close relatives of rolly pollies and "pill bugs," with a few adaptations for living on the ocean floor in the deep, cold waters of the Atlantic and Pacific Oceans. They have seven pairs of legs and four sets of jaws and can grow to more than two feet in length.

As scavengers, the animals are built to survive long periods between meals.

"Giant isopods are always in a state of semihibernation because they don't know when they can eat, so they limit their energy on breathing and other activities," marine ecologist Taeko Kimura tells Japan Times. "For that purpose they sometimes keep a large amount of fat in their livers, so maybe No. 1 still has a source of energy in its body, and that's why it still has no appetite."

But aquarium staff are concerned, especially as the tank No. 1 is in previously housed a healthy, and hungry, giant isopod. The artificial seawater it contains is "highly unlikely to generate organic substances" to sustain the animal, Japan Times notes.

Could someone be sneaking food to No. 1 — perhaps in an odd show of allegiance to the old British TV show The Prisoner? Or could it somehow be living on the err... effluvia of its fellows? Somehow, this mysterious animal, which Sea and Sky calls "without a doubt one of the strangest creatures found in the deep sea," has managed to keep some of its secrets.